Question

我制作插件来打开XML并读取它，然后解析它以显示一些信息，这是我使用的代码

from PyQt4 import QtCore, QtGui
from ui_latih import Ui_latih
import xml.etree.ElementTree as ETree
# create the dialog for zoom to point


class latihDialog(QtGui.QDialog):
    def __init__(self):
        QtGui.QDialog.__init__(self)
        # Set up the user interface from Designer.
        self.ui = Ui_latih()
        self.ui.setupUi(self)

        cariButton = self.ui.btnCari
        QtCore.QObject.connect(cariButton, QtCore.SIGNAL('clicked()'),self.cari)

    def cari(self, event=None):

        #open dialog
        filename = QtGui.QFileDialog.getOpenFileName(self, 'Open File', '*.xml')

        self.ui.lineFile.setText(filename)

        #panggil isi data
        self.isiDataFile(filename)

    def isiDataFile(self, nmfile):
        #buka dengan open mode baca
        teksFile = open(nmfile, 'r').read()

        self.ui.textFile.setText(teksFile)

       #parse XML FIle
        self.parsethis(teksFile)

    def parsethis(self, parse):
        doc =  ETree.fromstring(parse)
        for elem in doc.findall('{Default_Config/gco#}Integer'):
            a=elem.tag, elem.text
        print a


        self.ui.lineSkala.setText(a)

我解析了一个大的xml文件（打印时总共14页）和我要解析的一行显示如下

<gmd:denominator>
<gco:Integer>ValueScale</gco:Integer>
</gmd:denominator>

我想将ValueScale放在QlineEdit中显示，我收到错误信息：

File "C:\Users\Mr.Pakde/.qgis2/python/plugins\latih\latihdialog.py", line 65, in parsethis
    self.ui.lineSkala.setText(a)
UnboundLocalError: local variable 'a' referenced before assignment

有人可以帮助我吗？

Answer 1

问题可能在于：

   for elem in doc.findall('{Default_Config/gco#}Integer'):
            a=elem.tag, elem.text
        print a

   self.ui.lineSkala.setText(a)

如果doc.findall返回None，则不会a。您需要检查是否存在：

try:
    self.ui.lineSkala.setText(a)
except (UnboundLocalError, NameError):
    do_here_something_else...

使用元素树在插件QGIS中解析XML时的UnboundLocalError

1 个答案: